System for solvent extraction of oil or the like from solid organic particles



G. B. KARNOFSKY April 30., 1957 2,790,708 SYSTEM FOR SOLVENT EXTRACTIONOF OIL OR THE LIKE FROM SOLID ORGANIC PARTICLES 2 Sheets-Sheet 1 FiledJune 25, 1949 g} INVENTOR Georg' e 5! lfirpofslry 4 1473 My flu.

April 30, 1957 G. B. KARNOFSKY' 2,790,703

' SYSTEM FOR SOLVENT EXTRACTION OF OIL OR THE .LIKE FROM SOLID ORGANICPARTICLES Filed Jun 25, 1949 2 Sheets-Sheet 2 v T .55" 51" 5.6 F" a l lpiinii uii I II 54 miuavws i; l 55 Hqlminh 4. ukllgfiimulh I l luuul411m 27 INVENTOR 6 e 0/1995. /fa/ noFs/ry SYSTEM FOR SOLVENT EXTRACTIQNOF 01L UR THE LIKE FROM SOLID ORGANIC PARTHCLES George B. Kamofsky,Oakrnont, Pa, assignor, by means assignments, to Blow-Knox Company,Pittsburgh, Pa, a corporation of Delaware Application June 25, 1949,Serial No. 101,457

13 Claims. (ill. 23-310) The present invention relates to the solventextraction of extract from organic substances such as cotton seeds,soybeans, other vegetable seeds and nuts and other substances. Moreparticularly, it relates to an unobvious and unique organization ofexisting basic processing elements into a new combination, sooperatively related that certain difficulties, heretofore found mosttroublesome, are overcome and certain additional advantages in the wayof recovery of materials and economies in operation are obtained.

The usual solvent extraction system includes apparatus for extraction,for desolventizing the final solution of an extract such as oil(designated as miscella) and for desolventizing the residual solids, andin all such systems solvent is recycled to the extractor, in closedpaths, from the miscella desolventizer and from the solids desolventizerrespectively. Customarily in this art the extractor is physicallyseparated from the two desolventizer systems and functions as anextractor discretely, the parts, however, being interconnected forcontinuity of flow by conveyors, pumps, pipes, condensers, surge tanksand the like. The solids desolventizing apparatus has been a source oftroublesome fine solid particles in the vapors and additional dustseparating or vapor scrubbing apparatus has been found necessary toprevent fouling of condensers and vapor conduits. Moreover, the recoveryof such fines has not been satisfactory, and their disposal haspresented a problem. By the unique combination of this invention anintegral and simpler system is obtained in which substantially all solidmaterials are recovered, the problem of handling fines-laden vapor isovercome, and many, if not most, of the above-mentioned auxiliaryspecialized devices ordinarily required are eliminated with greatlyreduced cost of equipment, with reduced size of structures to house theequipment, and with increased thermal efliciency.

The system of this invention also provides for automatic maintenance ofthe optimum temperature for extraction, which usually is substantiallyat the boiling point of the solvent. It is, of course, common practiceto conduct extraction at elevated temperature but heretofore specializedheating means have been required to provide it, and in conventionallyorganized systems using a vented extractor, operation is limited to sometemperature below the solvent boiling point. In my system themaintenance of the desired higher temperature substantially at thesolvent boiling point is inherent in the organization of theparts, andthe increased temperature noticeably increases the efficiency ofextraction.

These and other objects and advantages of this extrac-' tion system willbe apparent from the following description of a specific embodiment,schematically shown in the following drawings, in which,

Figure l is a diagrammatic illustration of a plant embodying the systemof this invention with a portion of the internal structure of theextractor and desolventizer used therein more fully shown;

Figure 1A is a horizontal sectional partial plan View nited StatesPatent 0 Patented Apr. 3@, 1957 ice - 2 on a somewhat enlarged scaletaken along line lA-IA of Figure 1;

Figure 1B is a-vertical sectional view taken along line llB-lB of Figure1A;

Figure 2 is a View in vertical cross section taken along line IIII ofFigure 1 and shows a condenser suitable for use .with the plant systemillustrated in Figure 1;

'Figure 3 is a partial diagrammatic illustration of a modified form ofthe plant system of Figure l; and

Figure 4 is a view in vertical cross section taken along line IVIV ofFigure 3. a

The plant system of this invention consists of four essential elements,an extractorl, a solids desolventizer 2,.

a miscella desolventizer 3, and a vapor condenser 4, a preferred exampleof each of which will be presently described in detail. It will beobserved that the condenser 4, is connected directly to an extractorcasing 10, and that vapors are conducted from the solids and miscelladesolventizers to the condenser through this casing, which thusconstitutes a vapor collecting manifold. The condenser is mounted abovethe extractor and discharges condensed solvent directly into theextractor where it is used. Condensed water and any fine solids presentin the condensed liquids are also returned to the extractor and absorbedin the solid material in process. The vapor atmosphere passing throughthe extractor casing, in equilibrium with condensed liquid returned,automatically maintains the desired optimum extraction temperature ofsubstantially the boiling point of the solvent. 1

The extractor 1 is preferably of the type more fully described in mycopending United States patent application Serial No. 91,372, filed May4, 1949. In the embodiment shown in Figures 1, 1A and 2, it consists ofa casing 10, through the top of which duly prepared solid particles,such assoybean flakes, are fed from a feed hopper 11, by means of aninclined screw-conveyor tube 12, a screw 13, a spout 14, and inletflange 15, connecting the casing 1! to the conveyor. The overflow pointB, at the intersection of the tube 12 and spout 14, determines a liquidlevel AA in the conveyor casing; and the conveyor is of such length andinclination that the underflow point C at the intersection of tube 12and hopper 11 is below the level AA, forming a liquid trap. Solventsolution from extractor 1 or fresh solvent is also introduced into tube12, which is liquid tight, througha pipe 12a. Hence, a slurry of suchsolvent and flakes is maintained in the casing 12 of the screw conveyorand provides a vapor seal for the extractor. This slurry flows throughoutlet 14 and inlet flange 15 which is disposed appropriately forextraction purposes, as more specifically disclosed in the abovementioned application Serial No. 91,372.

Within extractor casing 10, a rotor 16 turns about its vertical axismoving successive cells 17 in a horizontal circular path. Each cell isopen at the top and is substantially closed during the major portion ofits rotation by a draining door 18 hinged along advancing edge 19thereof which allows each cell to drain continuously. Means (notillustrated) cause the respective doors 18 to open above a solids outlet20 in the bottom of extractor casing 10 after such drainage iscompleted.

This drainage of solvent and dissolved extract takes place into a seriesof compartments 21 radially divided from each other by partitions 22 inthe bottom of casing 10 underlying the path of travel of the cells 17.

In a preferred operation of extractor the contents or" the respectivecompartments are pumped out respectively through suction lines 23 bypumps 24 and delivered through outlet lines 25 to the appropriatelocations to obtain countercurrent flow of liquid relative the movementof particles in the respective cells 17. Nozzles 26 extend radiallyrelative the axis of rotor 16 and are conu nected respectively to theoutlet ends of lines and preferably are constructed to produce a sharptransfer of liquid flowing through each nozzle 26 as it passes over eachpartition 17a during the rotation of the cells 17 beneath that nozzle.

Condenser 4 has a casing 27 mounted invertical osition directly above avapor outlet 28 in the top of extractor 10. Condenser 4 is connected tothis vapor outlet by a conduit 29 which, in the embodiment shown,constitutes the lower portion of the shell 27 of the condenser. As shownin Figure 2 a plurality of U-shaped tubes 30 have their respective endsopening into the sealed compartments of a header 31 connected to theupper end of shell 27. A cooling medium such as liquid water enters thetubes through a line 32 connected to one of these compartments in heater31 and flows out through a line 33 connected to the other compartment.Dependent upon the temperature and flow of water through the tubes 30,temperature of the vapors including entrained material rising throughvapor outlet 28,

it is possible to condense all of the condensable portions of-thesevapors in condenser 4 returning them directly through conduit 29 andvapor outlet 28 to the cells 17 in extractor 2. A funnel distributor 82is positioned within extractor casing 10 beneath the lower end of vaporoutlet 28 and is fastened to the shell of extractor 10 by a suitablebracket 83. The lower open end of funnel distributor 82 is formed in theshape of a slot 84 which extends radially relative to the vertical axisof rotor 16. denscd liquids returning from condenser 4 between cells 17as the respective partitions 17a thereof pass beneath slotted opening84. Vapors rising in vapor outlet 28 first pass between the top ofdistributor 82 and the lower end of the vapor outlet.

Liquids condensed by condenser 4 fall in a direction counter to themovement of the vapors entering through outlet 28. This condensateeifectively scrubs the rising vapors and washes the vertical heattransfer surfaces within casing 27, so that entrained fine solidmaterials are returned to extractor 1 with the condensed liquids. Thenon-condensable gases in the vapors pass out of condenser 4 through avent 34. A fan 35 operated by a motor 36 may be connected to vent 34 toplace the entire plant under a slight subatmospheric pressure. Operationunder such a partial vacuum insures that if there should be any leakagein the system, there will be leakage of air into the system rather thanany escape of solvent vapor from the system. Substantially no air entersextractor 1 because of the slurry vapor seal in 4 conveyor tube 12.

Make-up solvent may be added to the system through a line 37 where itwill assist the condensable portions of the vapors passing intocondenser. 4 to wash down and maintain the condensing surfaces thereinclean as the condensed liquids run back toward extractor 1. Inletconnection 37 may preferably be so applied to casing 27 as to impart atangential and downwardly spiraling motion around the inside thereof tothe make-up solvent. Theamount of make-up solvent is usually very smalland may be added continually or periodically either through condenser 4as indicated or elsewhere as may be desired.

As the doors 18 of the respective cells 17 are successively opened overthe solids outlet 20, the solid residue in the cells including absorbedand adherent liquids in the form principally of solvent and Water passthrough outlet 20 and into a conduit 38 connected to one end of adesolventizer 2. In the solids desolventizer, the extracted particlesare heated until the solvent is substantially all evaporated, the vaporsthus generated passing upwardly through the outlet 20, and the extractorcasing 10, to the condenser 4, where they are recovered as liquidsolvent, as above described. Any convenient mode of heating the solidsmay be provided, but it is In this way, there is a sharp transfer of theconi 4 preferred for processing soybean flakes or the like to usesuperheated solvent vapors for this purpose; and the sohds desolventizer2, illustrated in Figure 1, is constructed to operate on that principle.This desolventizer is of the type more fully described in United Statesapplication Serial No. 737,915, filed March 28, 1947, now Patent No.2,571,143, in the name of Eugene H. Leslie. It is evident that othertypes of desolventizer may also be used.

In this desolventizer, which removes the vaporizable material from thesolids, in order that the solids may be made into finished meal or otherfinished form, the material passing through conduit 38 is fed andcascaded toward the other end of desolventizer casing 39 principally bya helically wound blade 40. The various turns of helical blade 40 areconnected by longitudinal bars 4-1 which terminate in plates 42 at theends of the desolventizer. Plates 42 in turn are rotated by means ofappropriate shafting and bevel gearing 43 driven by a motor which is notshown. Longitudinal scraper bars 44 extend between two vapor domes 45and assist in cascading the solids being progressively fed through sothat such solids fall through the vapor in the desolventizer used tovaporize residual liquids in those solids.

This vaporization is produced by the heating of the vapors rising invapor domes 45. These vapors pass through ducts 46 under the influenceof a fan 47 which blows such vapors through a heater 48 the lower end ofwhich opens into desolventizer 2 intermediate the two domes 45. Heater48 is a shell and tube type of heat exchanger, the tubes 49 of which areheated by steam which surrounds them, said steam flowing through thecasing of heater 48 through appropriate connections (not shown). Thevapors passing through fan 47 flow through the tubes 49 and intodesolventizer 2 in a superheated condition where they divide and flowtoward both ends thereof. This superheated vapor evaporates residualliquids from the solids and causes the net evolved vapor to pass upwardsthrough conduit 38 and solids outlet 20 back into extractor 1. Ifdesired, a separate connection may be made between solids desolventizer2 and extractor casing 10 through the bottom thereof or elsewhere forthe return of net evolved vapors from desolventizer 2 to extractor 1.The use of solids outlet 29 for this purpose is, however, to bepreferred. Since these vapors are substantially at the boiling point,extractor 1 can be maintained at optimum operating temperature duringthe extraction cycle. This optimum operating temperature issubstantially at the boiling point of the solvent used which in the caseof soybean flake is frequently commercial hexane, a substance whichboils at about 150 F.

The solids in desolventizer 2 successively progress until they pass outof the desolventizer through a conduit 50 where they fall between thevanes of a rotating valve 51. Valve 51 is turned by a motor 52 andsuccessively discharges the material in the compartments of the valveinto a pipe 53 which may lead to a conventional steam deodorizer beforeundergoing subsequent steps in the preparation of a finished solidproduct.

The miscella desolventizer 3 preferably consists of a preheater 57, anevaporator 59, and a vapor-liquid separator 65 seriatcly connected.Miscella constituting the final efiluent from extractor 1 is pumped outof the appropriate compartment 21 through a line 54 connected to theintake of a pump 55. Pump 55 forces the miscella through line 56 andthrough the heating coils of preheatcr 57 whence the preheated miscellapasses through line 53 into evaporator 59. Conventional miscella filterscan be interposed betweenpump 55 and preheater 57 for the purpose ofremoving fines and any other solid material that may be therein. Theheating coils in preheater 57 are heated by steam entering through line60 and exiting through a line 61. Such steam is delivered at theappropriate temperature and pressure by any suitable source which is notillustrated.

A steam connection 63 is used to admit steam to evaporator 59 betweenthe tube sheets therein to provide heat for the evaporation operation,the condensed steam leaving the evaporator through a line 62. Miscellaentering evaporator 59 from pipe 58 flows upwardly inside the tubes (notshown) of evaporator 59, evaporating the solvent and causing solventvapor and desolventized extract to pass out through pipe 64 to thevapor-liquid separator 65 where the solvent in vapor form and thedesolventized oil or other extract are separated. The substantially puresolvent in vapor form passes out of vessel 65 through a line 66 directlyconnected to extractor casing at vapor inlet 67. Extract from which notall solvent has been evaporated collects in vessel 65 and flows outthrough a line 68 whence it passes into conventional, stripping,deodorizing and condensing equipment for finishing.

The solvent vapor entering through inlet 67 mingles with net evolvedvapors rising in solids outlet 20 from desolventizer 2 and pass togetherthrough casing 10 to condenser 4. In the solids desolventizer 2 bothsolvent vapor and water vapor are generated (the water being derivedfrom the organic material) in substantially the same ratio as in aconstant boiling mixture of water and solvent. Hence, the addition tosuch vapors of pure solvent vapor through inlet 67 from the miscelladesolventizer 3 increases the solvent vapor to water vapor ratio to thepoint where preferential condensation of solvent (if any condensationoccurs at all) results in the event of some heat loss from the vapormixture and condensation of Water in the extractor is thus prevented.This is of relatively more importance at the start of an extractionoperation. It is upon the initiation of an extraction cycle thatpreheater 57, evaporator 59 and vessel 65 in themiscella desolventizer 3may preferably be used to recirculate hot substantially pure solventvapor through extractor casing 10 to rapidly raise the temperaturethereof to operating temperature. At other times, if it is desirable,solvent vapor from vessel 65 may be passed directly to condenser 4.

It will thus be seen that this invention solves the problem whichformerly attended the disposal of solid fines contained in condensedwater, conserves those fines and preserves the moisture content of theoutgoing extracted and desolventized particles to the same extent thatwater was originally contained in the particles delivered to extractor1, since under proper operating procedure substantially no condensedwater drains into the compartments 21. In addition, this inventiontremendously simplifies extraction plants as they have heretofore beenknown and eliminates the need for such conventional items of equipmentas the extractor discharge conveyor,

solvent supply tank, solvent decanter, solvent pump, vapor scrubbingdevices, and separate condensers for the solids and liquidsdesolventizers.

Under some circumstances, it may be desirable to remove condensed waterdirectly from the condenser and introduce it into the screw conveyormeans for feeding solid organic particles to the extractor. Thus, in themodification illustrated in Figures 3 and 4, the difference between themodified embodiment and the preferred embodiment illustrated in Figures1, 1A and 2, lies in the means for removing water in liquid phase fromthe condensate in condenser 4' and returning such water with any finestherein to the inlet of conveyor tube 12'. The parts of the modifiedembodiment illustrated in Figures 3 and 4 corresponding to elements inFigures 1 and 2 bear the same reference numerals, primed, and aresimilar in construction and purpose.

Thus, condenser 4 is supplied with vapors from extractorl' by a conduit28 which extends upwardly into condenser casing 27. A cone-shapedseparating wall 90 closes the space between the tube 28' and the casing27, being sealed at its lower end around the exterior of conduit 28 sothat it forms a basin 91 for receiving condensed liquid. A shield orcover 92, spaced somewhat above the upper end of tube 28', on supportingbrackets 93, shieldsthe opening from any direct shower of condensedliquid, which is thus directed into the basin 91. The :bulk'of thesolvent portion of the condensate (assuming a solvent lighter thanwater, such as hexane, is used) overflows into tube 28' and thus returnsto the extractor. Basin 91 has sufficient capacity to afford thenecessary settling time for the condensed aqueous part and solvent toseparate. Water, fine solids in aqueous suspensiomand a portion of thesolvent are withdrawn from the bottom of the basin 91 through pipe 94.The rate of removal of liquid through the pipe 94 preferably exceedssomewhat the rate of condensing aqueous vapors alone, and includessufiicient solvent withdrawn with the water and fines to prevent theformation of a watersolvent interface level in the basin 91. Thisprecaution precludes emulsion accumulation in the decanting basin, whichin time would otherwise tend to overflow into the pipe 28' along withsolvent.

The lower end of conduit 28' is positioned above a funnel distributor82' fastened to extractor casing 10 by a suitable bracket 83'. The loweropen end of funnel distributor 82 is formed in the shape of a slot 84which extends radially relative the vertical axis of rotor 16'. In thisway, there preferably is a sharp transfer of condensed solvent betweencells 17' as the respective partitions 17a thereof pass beneath theslotted opening 84. Vapors rising in vapor outlet 28 first pass betweenthe top of distributor 82' and the lower end of the conduit 28.

The aqueous portion of the liquid from basin 91 is continuously drainedthrough the line 94 which leads to the intake of a pump 95 whichdelivers the water, contained fines and some solvent through a line%into the lower end of hopper 11. Thus, the aqueous part and the finesmingle with the slurry of fresh solid organic particles and solventbeing fed respectively through hopper 11 and pipe 12a to conveyor tube12. The purpose of this modification is to take advantage of the mixingaction of the conveyor and thus to incorporate the water and fines intothe mass of flakes substantially homogeneously. As in the embodiment ofFigures 1 and 2, the aqueous part so recycled in this embodiment doesnot increase the ultimate moisture content of the solids leaving thesolids desolventizer, but causes all moisture to remain in the systemwithout detriment and, further, avoids the dehydration of the solidorganic particles which normally would otherwise occur.

Although I have illustrated and described preferred and modifiedembodiments of this invention, it will be recognized that some furtherchanges may be made therein without departing from the spirit of theinvention or the scope of the appended claims.

Iclaim:

1. In a solvent extraction system for solid organic particles, apparatuscomprising in combination, an extractor having a casing and a vaporspace therein, a movable carrier in said casing within said vapor spaceand spaced above the bottom of said extractor to support and drain saidparticles during movement thereof, a vapor outlet in said extractor, acondenser connected to said vapor outlet and adapted to condenseliquefiable vapors passing through said outlet, a conduit for returningcondensate from said condenser to said extractor, a solids outlet insaid extractor, a drained solids desolventizer vessel connected to saidsolids outlet and adapted to desolventize said particles from saidextractor after extraction, a conduit for returning at least a part ofthe net evolved vapors from said desolventizer to said extractor, meansfor feeding said particles to said extractor, and means for withdrawingliquid solutions of extract and solvent from said extractor below saidcarrier.

2. In a system for solvent extraction, apparatus comprising incombination, an extractor having a casing, a horizontally rotatingcarrier in said casing having draining cells for said particles and avapor space over a plurality of. said cells, a vapor outlet in saidextractor in communication with said vapor space, a condenser conmac snected to said vapor outlet and adapted :to condense liquefiable vaporsfrom said extractor, a conduit for returningcondensate from saidcondenser to said extractor above said cells, a solids outlet in saidextractor separate from said vapor outlet, a solids desolventizer vesselconnested, to said solids outlet and adapted to desolventize particlespassing through said solids outlet after extraction, a conduit forreturning net vapors evolved in said solids desolventizer to saidextractor, and means for withdrawing liquid solution of extract fromsaid extractorbelow said carrier.

3. In a system for solvent extraction, apparatus comprising incombination, an extractor having a casing, a horizontally rotatingcarrier in said casing having draining cells for said particles and avapor space around said cells, said cells being spaced above the bottomof said extractor, a vapor outlet adjacent the top of said extractor, acondenser connected to said vapor outlet for condensing condensableportions of vapors passing from said extractor through said vaporoutlet, miscella outlet means in said extractor below said carrier,means for separating substantially pure solventlin vapor form from themiscella passing from said extractor through said miscella outlet, apipe for returning said substantially pure solvent vapor directly tosaid extractor, a solids outlet in said extractor. and means fordesolventizing solids passing from said extractor, and means forreturning at least part of the net vapors evolved in said last mentionedmeans to said extractor through said solids outlet.

4. in a sealed solvent extraction system for solid organic particles,apparatus comprising in combination, an extractor having a casing, ahorizontally rotating carrier in said casing having draining cells forsaid particles and a vapor space around said cells, said cells beingspaced above the bottom of said extractor, a vapor outlet adjacent thetop of said extractor above said cells in communication with said vaporspace, a condenser connected to said vapor outlet and substantiallypositioned above said vapor outlet to return at least some condensate tosaid cells, a vent connected to said condenser and adapted to ventnon-condensable gases, a solids outlet adjacent the bottom of saidextractor, a solids desolventizer vessel connected to said solids outletand substantially positioned below said solids outlet, a liquids outletadjacent the bottom of said extractor below said carrier, inclinedconveying means for feeding said particles into said cells. saidconveying means including a fluid-tight casinghaving an outlet and aninlet Wholly below said outlet, and means for supplying liquid to saidcasing to fill it to a level below said outlet and maintain said inletsubmerged. whereby a slurry of particles and liquid is formed in saidconveying means to create a vapor seal and any leakage of solventoutwardly from said system through said casing is prevented.

5. In a system for solvent extraction, apparatus comprising incombination, an extractor having a casing, a horizontally rotatingcarrier in said casing having draining cells for said particles and avapor space around said cells, said cells being spaced above the bottomof said extractor, a vapor outlet adjacent the top of said extractor. anextracted solution outlet adjacent the bottom of said extractor belowsaid carrier, a solids outlet adjacent the bottom of said extractor, acondenser adapted to condense condensable portions of vapors passingfrom said extractor through said vapor outlet. a conduit connecting saidcondenser and said vapor outlet and adapted to return at least part ofsaid condensable portions so condensed to said extractor, a drainedsolids desolventizer vessel adapted to receive solids from saidextractor through said solids outlet and to return net evolved vaporsfrom said desolventizer to said extractor, evaporating means connectedto said extracted solution outlet and adapted to separate substantiallypure solvent vapor from extract, and a vapor pipe connected to said,.lastrnentioned means to return said substantially pure solvent vaportosaid extractor.

6. In a solvent extraction system for solid organic par ticles,apparatus comprising in combination, an extractor having an outsideeasing, a movable carrier in said extractor spaced above the bottomthereof to support and drain said particles during movement thereof, asolids outlet in said extractor, a drained solids desolventizer vesselconnected to said outlet, means for withdrawing net evolved vapors fromsaid desolventizer, a liquids outlet in said extractor below saidcarrier, a miscella desol vcntizer connected to said miscella outlet,and means for returning solvent in vapor form from said miscelladesolventizer to said extractor, whereby the temperature of saidextractor may be maintained substantially at the solvent boiling pointand the ratio of solvent vapor to water vapor in said extractor may bemaintained favorable in the event of any condensation to thepreferential condensation of solvent in the extractor.

7. In a system for solvent extraction, apparatus comprising incombination, an extractor having drainable cells rotatable about avertical axis with radial partitions therebetween, a vapor outletadjacent the top of said extractor, a liquids outlet adjacent the bottomof said extractor, a solids outlet adjacent the bottom of saidextractor, a condenser adapted to condense condensable portions ofvapors passing from said extractor through said vapor outlet, a conduitconnecting said condenser and said vapor outlet and adapted to admitsaid vapors to said condenser and to return solvent from saideondensable portions to said extractor, a decanting basin disposed insaid conduit so as to permit overflow of solvent liquid into saidconduit, a shield mounted in said conduit above said basin obstructingdirect downward flow of condensed liquid through said conduit, saidshield extending over said basin so as to direct condensed liquid intosaid basin, a drain connected to said basin, a funnel distributorpositioned beneath the lower end of said conduit in said extractor, saiddistributor having a radially slotted opening in the bottom thereofrelative the axis of said extractor, a solids desolventizer vesseladapted to receive solids from said extractor through said solidsoutlet, a conduit connecting said desolventizer and said solids outletand adapted to pass said solids to said desolventizer by gravity flowand to return vapors from said desolventizer to said extractor, aliquids desolventizer connected to said liquids outlet and adapted toseparate extract and solvent, and a conduit connecting said extractorand said liquids desolventizer and adapted to return solvent vapor tosaid extractor.

8. In a solvent extraction system for solid organic particles, apparatuscomprising in combination, an extractor having draining cells rotatableabout a vertical axis, a vapor outlet adjacent the top of saidextractor, a liquids outlet adjacent the bottom of said extractor, asolids outlet in said extractor, a condenser adapted to condensecondensable portions of vapors passing from said extractor through saidvapor outlet, a conduit connecting said condenser and said vapor outletand adapted to admit said vapors to said condenser and to return solventfrom said condensable portions to said extractor, a decanting basindisposed in said conduit so as to permit overflow of solvent liquid intosaid conduit. a shield mounted in said conduit above said basinobstructing direct downward flow of condensed liquid through saidconduit, said shield extending over said basin so as to direct condensedliquid into said basin, a drain connected to said basin, means forfeeding solid organic particles to said extractor, said drain beingconnected adjacent said means to return the aqueous part of saidcondensed liquid to said particles, :1 solids desolventizer vesseladapted to receive solids di rectly from said extractor through saidsolids outlet and to return net evolved vapor from said desolventizer tosaid extractor, and means connected to said liquids outlet and adaptedto separate substantially pure solvent vapor from extract, and means toreturn said substantially pure solvent vapor to said extractor.

9. In a solvent extraction system for solid organic particles, the stepscomprising in combination, moving a support on which solid organicparticles rest their weight to carry them through a vapor space in asolvent extraction zone, supplying said particles with solvent anddraining said particles during said carrying, removing and immediatelycondensing vapors from said zone, directly returning at least a portionof the resulting condensate to said zone, removing said particles fromsaid zone after extraction, desolven'tizing said particles so removed inthe presence of heat, directly returning evolved vapors from saiddesolventizing to said zone, removing extract solu* tion from said zonebelow the level of said particles during said carrying, separatingsubstantially pure solvent in vapor form from said solution, andreturning said solvent in vapor form to said zone at least during theinitiation of an extraction cycle.

10. In a system for the solvent extraction of solid organic particles,the steps comprising, in combination, moving a support on which solidorganic particles rest their Weight to carry them through a vapor spacein a solvent extraction zone, repeatedly supplying said particles withliquid containing solvent during said carrying, draining oil liquidbelow said particles respectively during said carrying, discharging saidparticles from said extraction zone, passing said particles into asolids desolven'tizing zone, evaporating liquid from said particles insaid solids desolventizing zone, returning at least some of saidevaporated liquid in vapor form to said vapor space in said extractionzone, and removing from said extraction zone liquid drained from saidparticles in said extraction zone, said removing being below the levelof said particles during said carrying and occurring during saidcarrying.

11. In a system for the solvent extraction of solid organic particles,the steps comprising, in combination, moving a Support on which solidorganic particles rest their Weight to carry them through a vapor spacein a solvent extraction zone, repeatedly supplying said particles withsolvent solution during said carrying, draining oil solvent solutionbelow said particles respectively during said carrying, discharging saidparticles from said extraction zone, passing said particles into asolids desolventizing zone, evaporating residual liquid from saidparticles in said solids desolventizing zone, returning at least some ofsaid evaporated liquid in vapor form to said vapor space in saidextraction zone, withdrawing solvent solution drained from saidparticles in said extraction zone below the level of said particlesduring said carrying, generating vapor from said last-mentioned solventsolution, and returning at least some of said last-mentioned vapor tosaid vapor space in said extraction zone.

12. In a system for the solvent extraction of solid organic particles,apparatus comprising, in combination, an extractor having a casing, saidcasing having a vapor space therein, movable carrier means within andspaced from said casing to support said particles within said vaporspace and spaced away from said casing, means for feeding said particlesonto said carrier means, means for supplying liquid to said particlescarried by said carrier means, receiving means beneath said carriermeans to receive and discharge liquid draining from said particles belowthe particles support level of said carrier means, a solids outlet forsaid particles, means for discharging said particles from said carrierinto said solids outlet after said carrier means has moved to apredetermined extent, a solids desolventizer connected to said solidsoutlet to receive said discharged particles, and means for returningvapor from said solids desolventizer to the interior of said casing.

13. In a system for the solvent extraction of solid organic particles,apparatus comprising, in combination, an extractor having a casing, saidcasing having a vapor space therein, movable carrier means within andspaced from said casing to support said particles within said vaporspace and spaced away from said casing, means for feeding said particlesonto said carrier means, means for supplying liquid to said particlescarried by said carrier means, receiving means beneath said carriermeans to receive liquid draining from said particles, a solids outletfor said particles, means for discharging said particles from saidcarrier into said solids outlet after said carrier means has moved to apredetermined extent, means for relatively moving said carrier meansbetween said means for feeding and said means for discharging, saidparticles and carrier means being substantially without movementrelative to one another during movement together between the position ofsaid means for feeding and the position of said means for discharging, asolids desolventizer connected to said solids outlet to receive saiddischarged particles, means for withdrawing liquid from said receivingmeans below the particles support level of said carrier means, means forevolving solvent vapor from said withdrawn liquid, and means forreturning solvent vapor so evolved to the interior of said casing.

References Cited in the file of this patent UNITED STATES PATENTS 97,059De Lime Nov. 23, 1869 1,081,949 Dupont Dec. 23, 1913 2,264,390 Levine etal. Dec. 2, 1941 2,447,845 Dinley Aug. 24, 1948 2,554,109 Langhurst May22, 1951 FOREIGN PATENTS 670,283 Germany Jan. 16, 1939

9. IN A SOLVENT EXTRACTION SYSTEM FOR SOLID ORGANIC PARTICLES, THE STEPSCOMPRISING IN COMBINATION, MOVING A SUPPORT ON WHICH SOLID ORGANICPARTICLES REST THEIR WEIGHT TO CARRY THEM THROUGH A VAPOR SPACE IN ASOLVENT EXTRACTION ZONE, SUPPLYING SAID PARTICLES WIT H SOLVENT ANDDRAINING SAID PARTICLES DURING SAID CARRYING, REMOVING AND IMMEDIATELYCONDENSING VAPORS FROM SAID ZONE, DIRECTLY RETURNING AT LEAST A PORTIONOF THE RESULTING CONDENSATE TO SAID ZONE, REMOVING SAID PARTICLES FROMSAID ZONE AFTER EXTRACTION, DESOLVENTIZING SAID PARTICLES SO REMOVED INTHE PRESENCE OF HEAT, DIRECTLY RETURNING EVOLVED VAPORS FROM SAIDDESOLVENTIZING TO SAID ZONE, REMOVING EXTRACT SOLUTION FROM SAID ZONEBELOW THE LEVEL OF SAID PARTICLES DURING SAID CARRYING, SEPARATINGSUBSTANTIALLY PURE SOLVENT IN VAPOR FORM FROM SAID SOLUTION, ANDRETURNING SAID SOLVENT IN VAPOR FORM TO SAID ZONE AT LEAST DURING THEINITIATION OF AN EXTRACTION CYCLE.